"You were right," said Kenmore.
The jeep plunged on. Its wheels clanged and bounced on the dust-covered stone beneath them; its headlights glared ahead. But the sensation of the ride was essentially that of a dream. In one-sixth gravity, no object falls fast. Upward bumps were abrupt, but landings were gentle; on the moon, an object falls less than three feet during its first second of free descent. This flight was like a nightmare.
"What . . ."
"Look behind!" Kenmore snapped.
Moreau flung himself to a port, stared, and his breath left him: The half-mile-high, light-streaked precipice was crumbling before his eyes. It bulged; it leaned outward. Swiftly spreading cracks ran everywhere; gigantic masses of stone stirred in movement which was the more horrible because there should not ever be any such motion on the moon—movement which was not the motion of men or their machines.
It seemed that the cliff did not so much crumble downward as outward. It loomed above the fleeing jeep and shut out the stars; then it came down like the paw of some utterly monstrous creature.
But there was enormous deliberation in all save the frenzied flight of the jeep; the stony masses descended in slow motion. Objects on the moon fall approximately two and a half feet in the first second of fall, and roughly five in the next, and a little more than ten in the third. The flying fragments of the cliff seemed almost to float above the racing vehicle; but they descended, too, and their mass was monstrous. Kenmore somehow spared a hand to flip the controls that would close steel shutters over all the ports save those before him. They were meant for use in daylight against the baking heat, but they might protect the plastic ports.
Something hit a wheel; something incredible brushed the rearmost part of the cabin. Stones, rocks, boulders flew on before it, and settled almost deliberately to the ground—and the violence of their impact was proved by their splintering even as they bounced.
The jeep veered to one side to avoid a mass as big as a house, which landed a hundred yards ahead. It was too big to bounce, brittle with the more-than-liquid-air frigidity. The mass disintegrated as it touched, and instants later the jeep jolted crazily as its wheels ran over the spreading fragments.
Then the spotty earthlight itself—filtering through hurtling debris—was blotted out. Kenmore swore as something taller than the jeep hurtled down before the driving-ports, and rolled onward, shedding parts of itself as it rolled. It seemed to waddle and carom between stony walls on either side. The clamor of stones falling on the jeep's steel body rose to an uproar in which one could not hear himself think.
Kenmore braked, his face twisted in a grimace; then he followed the monster closely. And suddenly the drumming of rock-splinters diminished. It almost ended —then there was an outrageous crash as some unseen missile struck. Afterward, there were merely sharp patterings of particles ranging from the size of one's fist to sand grains; then silence. In the sudden quiet a wheel thumped violently; the last impact had been upon it. Kenmore tensed, noting how bad the thump sounded. In any case, repair was impossible. Presently he stopped.
CHAPTER II. EMERGENCY LANDING
MOREAU crawled from where he had been flung by the gyrations of the jeep and stared at the dimly glowing instrument board, where Kenmore's eyes, also, were fixed. In the back of the jeep something clicked; there was a sighing as the air apparatus worked briefly. But the air pressure indicator did not stir; incredibly, the jeep was not losing its air to the vacuum outside. The plastic-glass-wool layers between inner and outer hulls had sealed off any cracks that may have come in the outside plating.
"That blast was fired too soon," said Joe Kenmore. 'If we'd had one wheel all the way over the rock we stopped at, we'd be buried now."
Moreau swallowed. "A wheel—is bent," he said thinly. "Do you think we can return to the City on it?"
"No use even looking," Kenmore told him. "Well run on it until it collapses—if it does. If the wheel falls off, that's that."
Moreau swallowed again. "That flash could have been a meteor. A meteor could have struck the top of the cliff . . ."
"Only it didn't," said Kenmore, savagely. "Vaporized iron wouldn't give a pure white light. That was magnesium marking-powder in liquid oxygen; we could make blasts like that!"
He had named the explosive which was at once the safest to ship by rocket—it is utterly harmless unless the ingredients are mixed—and the one whose constituents were normal supplies for Civilian City. Oxygen, of course, was for breathing; magnesium powder for a stalled jeep to spread over square miles of moondust by airjet, to mark its position so that it could be seen from space. No jet had thus been helped yet—before its crew was dead—but there was still hope.
"Then it was . . ." Moreau lapsed into infuriated syllables in his own language. If somebody had blasted down a cliff to destroy this jeep and murder its crew, some profanity was justified.
"That was meant to kill us, yes," said Kenmore. "It'll be interesting to find out who, besides us, was roaming around outside in a jeep. They'll be our would-be assassins."
He opened a drawer and took out the large-scale, space-photographs which were at once the maps and the surveys of this general area of the moon's surface.
After a time, Moreau said slowly, "Of course it could be that there are enemies of Civilian City who do not live in the City itself."
Kenmore said nothing. He clipped a photo to the map rack, where he could see it clearly, and began to edge the jeep out of its still-unpleasant situation. The gigantic stone directly before them was surrounded by debris; boulders of all possible dimensions encircled it. The jeep could ride, lurching violently, over the smallest of these; it could get around some, and a few could be crossed by straddling. The rest had to be avoided altogether, if possible.
"Our would-be murderers," said Moreau unhappily, "could be fellow citizens of the City who disapprove of the entire project of which they are a part. Or they could be from Earth, secretly landed and operating from a base somehow established without the radars having detected them. But there are still some who say that the United States does not enjoy having people of other nations on the moon. They say that your—ah—military men may contrive accidents to be discouraging."
"You don't believe that!" snapped Kenmore.
"No," admitted Moreau, "I do not. Nor do I believe in a secret base established by our enemies. But some will say that the United States works covertly to sabotage the project to which it admitted other countries. The proposition is foolish, but it is believed."
Kenmore grunted. There was a crisis on Earth, which it was hoped the moon project would conquer. There had been twenty-odd known civilizations on Earth in the past, he recalled, and everyone had reached a point of crisis and collapsed. China and Babylonia, Greece and Rome rose and fell—and they were at least as much civilizations as nations. Current, Western civilization was built on mechanical power rather than on human muscles; it had risen higher than any others. With power enough, men could make Earth a garden, and colonize the stars. Man not only can do this, Kenmore thought; man must do it, or this civilization will decay. Civilization must climb, or die!
But there was the question of power—its foundation. Coal and oil were limited; only atomic energy promised to let progress continue. Only atomic power involved radioactivity, and radioactivity meant danger. Already the background-count of splitting atoms in the atmosphere had multiplied eight times from the relatively trivial power-reactors in use. No matter how careful the screening, or how painstaking the disposal of atomic wastes, a steady trickle of atomic poison seeped into the air. There was a limit to the power that could be produced without destroying all life on Earth, and that limit had nearly been reached—without releasing enough power so that human civilization could continue to rise.